What are the steps in a posterolateral neck dissection?

Posterolateral Neck Dissection: Surgical Technique

Posterolateral neck dissection is a regional lymphadenectomy that removes retroauricular and suboccipital lymph nodes in continuity with the upper posterior triangle and jugular chain contents, primarily indicated for posterior scalp and skin malignancies posterior to a coronal plane through the ear canals. 1

Anatomical Boundaries and Extent

The dissection encompasses the following nodal regions:

• Retroauricular (postauricular) lymph nodes - located behind the ear 1
• Suboccipital lymph nodes - at the base of the skull posteriorly 1
• Upper posterior triangle contents (Level V) - the posterolateral cervical region 1, 2
• Jugular chain nodes (Levels II-IV) - when performed as part of comprehensive dissection 2

Surgical Technique Steps

Patient Positioning and Incision

• Position the patient supine with neck extended and head turned away from the operative side 1
• Create an incision that provides adequate exposure of the retroauricular, suboccipital, and posterior triangle regions 1

Preservation of Key Structures

• Preserve the spinal accessory nerve (cranial nerve XI) throughout the dissection - this is critical to minimize shoulder morbidity 1, 3
• Preserve the splenius capitis muscle 1
• Preserve the sternocleidomastoid muscle 1

Lymph Node Removal

• Remove retroauricular and suboccipital lymph nodes en bloc 1
• Continue dissection to include upper posterior triangle contents in continuity with the specimen 1
• Include jugular chain nodes (Levels II-IV) when indicated based on tumor extent and nodal staging 2

Specimen Handling

• Orient the specimen to identify specific lymph node levels for accurate pathologic staging 4

Indications Based on Clinical Staging

The extent of posterolateral neck dissection varies by nodal stage:

N0 Disease (Clinically Node-Negative)

• Perform selective dissection of at-risk nodal basins including retroauricular, suboccipital, and Level V nodes 5
• This approach is appropriate for elective treatment of posterior scalp melanomas and squamous cell carcinomas 6

N1-N2 Disease

• Perform either selective or comprehensive dissection based on tumor burden 5
• Comprehensive dissection should include all at-risk levels (II-V plus retroauricular/suboccipital) 2

N3 Disease

• Perform comprehensive dissection including all at-risk levels 5

Bilateral Considerations

• Perform bilateral posterolateral neck dissections for midline posterior scalp tumors where both sides are at risk for metastases 7

Expected Outcomes and Morbidity

Regional Control

• Regional disease control is achieved in 89-93% of patients when posterolateral neck dissection is performed as part of multidisciplinary treatment 2, 6
• Regional recurrence within the dissected field occurs in less than 10% of cases 2, 6

Functional Outcomes

• Shoulder pain occurs in approximately 35% of patients postoperatively 3
• Only 50% of shoulder pain cases are attributable to spinal accessory nerve dysfunction, emphasizing the importance of nerve preservation 3
• Significant shoulder abduction limitation (>40° difference) occurs almost exclusively when the spinal accessory nerve is damaged 3
• Cosmetic and functional results are generally good when key structures are preserved 1

Critical Pitfalls to Avoid

• Do not sacrifice the spinal accessory nerve unless directly invaded by tumor - nerve preservation dramatically reduces shoulder morbidity 1, 3
• Do not perform inadequate dissection in N3 disease - comprehensive dissection of all at-risk levels is mandatory 5
• Do not neglect bilateral dissection for midline tumors - both sides require treatment 7
• Examine trapezius muscle function and bilateral shoulder abduction postoperatively to detect spinal accessory nerve injury early 3

Adjuvant Therapy Requirements

• Administer postoperative chemoradiation for extracapsular extension or positive margins 5
• Administer postoperative radiation for multiple positive nodes without extracapsular spread 5